My 2010 rmx 450z stalls when put into gear

SOURCE: gear/clutch problem

does not seem like the waterpump. is the clutch set too loose?
usually in wire based clutches, if the clutch cable is set to be too loose, or if it is frayed, and needs replacement, the bike will jump and stall.
check that.

SOURCE: clutch engaged engine stalls 2003 Suzuki GSX-R 1000

The bike has a sidestand interlock that prevents you from riding away with the kickstand down. That interlock is not functioning properly. Could have been bent or moved, unplugged, or perhaps the relay has failed. If physically activating the switch does not work, and connecting the wires with a jumper does not work start looking at the turn signal relay, some bikes have that circuit integrated into the relay.

SOURCE: clutch engageing at start up

if your clutch is adjusted properly, it should not be doing that anyway, even if it is contaminated with gasoline. make sure clutch is properly adjusted, and if that doesnt work you made need to remove the clutch plates and clean them and lightly sand them to remove the fuel from the composite plates, fuel on them will make clutching operation jerky. they will clean themselves over time and a few oil changes if thats easier for you

SOURCE: Engine Stalls when put in Gear, Suzuki GSX-R 1000 K3 (2003)

Most of the safety systems use a diode pack in the loom to stop clutch and side stand switch etc from back feeding each other. Maybe this has failed. If not could it be in the loom, a broken or shorted wire. Look for a tight bend in the route the loom runs and external damage to the tape.

SOURCE: i have a 07 Gsxr

The clutch cable is the first place to check as it's a high failure rate part and also the easiest to fix. It you can see the clutch arm with the bike assembled, pull the handelbar handle and see if the arm moves all the way. under the counter shafts sprockets cover is the arm and it's adjustment screw it could have backed out or is brocken. You may be able to remove this cover and watch it operate. Does the handle bar lever pull in with the normal amount of play and feel? Most bikes that have been sitting though the winter can have stuck and now the cable or the clutch is stuck or broken. The clutch that was working and not the very next use probly not the clutch it's self but the cable and or the handle bar or linkage. Remove the cable and see if it moves smoothly if it binds at all or catches or requires any force to move or turn the cable in the housing it's bad and needs to be replaced. the aftermarket cables are cheaper and better than orginal equipment and can be aquired though the bike bandit ONLINE In the USA they ship to you in a few days and if your an AMA motorcyclist member you can get a 10 % discount and if your all the time rider the other benifits will helpyou too.